The invention relates to modified
biomass charcoal and a remediation method of heavy
metal contaminated soil. The modified
biomass charcoal is prepared by the following steps: (1) sieving
biomass charcoal, and washing so as to remove surface fly dust and impurities until the pH value of a scrubbing solution is 6.5-7.5; (2) uniformly mixing the biomass charcoal and a
phosphoric acid solution according to the
mass ratio of 1 to (1.5-2.5), and then soaking at
room temperature for 24 hours above, wherein the
mass percent concentration of the
phosphoric acid solution is 10-40%; and (3) carrying out
solid-liquid separation on the soaking solution, and then
drying the obtained a
solid material, namely the modified biomass charcoal. The modified biomass charcoal is reasonable in design, is simple in technology, and overcomes the technical difficulty for a long time;
phosphoric acid is detained in the biomass charcoal in the form of
metaphosphoric acid, and especially can form
sediment substances together with active heavy
metal ions under a water containing condition, thereby intensifying the
passivation or fixing effect to the heavy
metal ions by the biomass charcoal.